Process of recovering high-grade wood rosin



grinding wood moving beinar 4 some of the objectionable Patented May 28, 1929.

UNITED STATES PATENT OFFICE.

HARRY E. KAISER AND ROY S. HANCOCK. OF KENVIL, NEW JERSEY, ASSIGNORS TO HEBCU LES POWDER COMPANY, DELAWARE,

PROCESS OF RECOVERING HIGH-GRADE WOOD ROSIN.

No Drawing. Application filed August 18, 1926, Serial No. 130,103. ReneweiAugust'g, 1928.

is so thoroughly purified and refined that it 10 is adapted for use in the manufacture of high grade rosin soaps and limed varnishes of satisfactory color, as well as for most, if not all, other purposes for which gum rosin is adapted.

A known process of producing vwood rosin of a lower grade, and the process that we preferably, but not necessarily, employ as a preliminary process in the manufacture of our more highly refined rosin, consists in and stumps from pine trees, placing the wood stock in large digesters,

assing steam through the stock and thus riving off a. considerable quantity of turpentine, fio 'ng the stock with gasoline or 25 other solveiilrthereby extracting certain marosin, pine oil and variousv terials, chiefly color bodies, passing the gasoline solution, commonly known as drop liquor, through suitable evaporators, and fractionally rethe gasoline and pine oil. The ine oil produced by the distillation is re ned and sold. The recovered gasoline is again used in the process.

The recovered rosin is a marketable prodnot, but is not satisfactory. for sizing the highest grades of paper'or in making the higher 1grades of varnish, and therefore must eted at a relatively low price.

means of 'a preliminary distillation, coloring matter may be removed. By distilling under a high vacuum at a temperatureof from 475650 F., preferably 550600 'F., and tractionally condensing at temperatures of about 400 F.', 350 F. and 300 F., three grades of rosin are recoverable, the highest grade being adapted for use in the manufacture of varnish and the higher grades of paper. The proportion of high grade rosin that is re coverable by this process, however, is substantially less than is recoverable by our gprocess, and such rosin is not of a sufiiciently igh grade to be adapted for use in the manufacture of highgrade rosin soaps and limed varnishes of satisfactory color, nor does such rosin have certain characteristics peculiar. to the high grade rosin "produced by our process, which characteristics willbe hereinafter fully set forth.

In the practice of may be first subjected to any desired distillation process, but such preliminary distillat'ion is unnecessary, and it is preferred to omit it. y

Our process comprisesfthe formation of a solution of gasoline or other light petroleum distillate, rosin and furfu'ryl alcohol, its cooling or refrigeration with resultant separation of furfuryl alcohol and coloring bodies, and the recovery of high grade rosin from the remaining solution. The process maybe carried out in a single operation, or in two or more operations. It is convenient and economical to divide the process into two operations, and it will be so described as a preferred way of practicing the process. Our process also contemplates, as a minor step, the conversion'of the larger part of verted into high grade rosin, and which is of low grade, into medium grade rosin, but such medium. grade rosin does not have the peculiar characteristics of the high grade rosin hereinafter claimed. Our process also contemplates the recovery and re-use of i e furfuryl alcohol as well as the gasoline;

15 pounds of rosin ounds of gasoline. -With this composition 1s thoroughly mixed (say) 11 pounds of furour process, the rosin OF WILMINGTON, DELAWARE, A CORPORATION Olli such minor part of the rosin as is not'conare added to (say) .85 I

furyl alcohol. We start, therefore, with the following composition (A) g rounds.

Gasoline I 85 Rosin "Q15 Furfuryl alcohol Ill The mixture should be heated, preferably about 115 F. At this temperature a homogeneoussolutionis formed. The solution is then cooled to a moderate atmospheric temperature (say 60 F.), at which temperature more or less of the furfuryl alcohol is thrown out of solution. A rough or preliminary gravity separation can now be made and which results in a separation into layers. The undissolved turfuryl alcohol settles to the bottom, carrying with it most of the color bodies. About twenty per cent of the 'rosin and a little gasoline is also carried down with the furfuryl alcohol. The upper layer is a homogeneous solution of gasoline,

rosin and furfuryl alcohol. Typical compositions of the two layers would be as follows (ignoring the small proportion of gasoline that is carried down by the furfuryl alcohol, and "bearing in mind that the amounts of rosin ahd furfuryl alcohol in each layer are only approximate) Upper layer (B).

Pounds. Gasohne 85 Rosin 12 F urfuryl alcohol 4. 25

. Lower layer (0 Pounds. Dark rosin 3 Furfuryl alcohol 6.75

To the solution (B) resulting from the first treatment is now added more furfuryl alcohol, say 11 pounds, giving the following composition (D): I

\ Pounds.- Gasoline 85 Rosin; 12

Furfuryl alcohol 15.25

To this mixturewhich comprises rosin and gasoline in solution in the undissolved fur- 5 furyl' alcohol heat need not be applied, but it'should be agitated to obtain a thorough washing of the solution by the undissolved ,furfuryl alcohol, and is then-cooled down to about 10 F. in order to throw dissolved 40 furfuryl alcohol out of solution and enable as complete a separation as possible; the

solubility of furfuryl alcohol in gasoline decreasing with decrease of temperature. The

mixture is then allowed to settle into layers. The undissolved furfuryl alcohol, which is by far the largest proportion of the furfuryl alcohol, settles to the bottom, with someof the rosin and the remaining coloring bodies. The upper layer is a homogeneous solution of gasoline and rosin, with a little furfuryl alcohol. Typical (approximate) compositions of the two layers are:

Upper layer (B).

cally, it is possible to dissolve rosin in gasoleaving a purified, highest grade rosin having the characteristics, hereinafter described, that distinguish the. same from all other heretofore known wood rosins. The re covered gasoline and 'furfuryl alcohol are then rc-used .in the process.

Compositions (C) and (F), being the precipitates of the two described treatments. are then (preferably) mixed, giving the following (approximate) composition 75 Pounds. Dark rosin 4. 5 Furfuryl alcohol s- 19.875

The furfuryl alcohol is distilled off, leaving a dark or low grade rosin. The furfuryl alcohol is re-used in the process.

The low grade rosin may be dissolved in (say) 28 pounds of gasoline and the gasoline-soluble rosin extracted. The insoluble residue is a very dark, brittle substance, being about 5% of the original rosin (say .75 pounds). From the gasoline-rosin solution, the gasoline is distilled off, leaving about 3.7 5 pounds of a medium grade rosin, being about 25% of the original rosin. The recovered gasoline is re-used in the process.

While the above figures show a recovery of of the original rosin as high grade rosin, the percentage of recovery by the. 5 practice of the process ranges from 7.0%. to

While we have illustrated one way of carrying out the process involving two treatments, in the first of which the mixture of gasoline, rosin and furfuryl l is heated to a relatively high temperiifla' and then cooled to a medium temperature, followed by a gravity separation, and in the second of which the lighter product of the separation is refrigerated, followed by a gravity separation, it should be understood that the process is capable of being carried out, although with less economy of heat, by a single refrigerating treatment, preferably preceded by heating to insurea good homogenous solution, and followed by a gravity separation. It is also feasible, andmay be in some cases advantageous, to increase the number of stages in the treatment. That is, there may be a succession of more or less rough separations'of the character described, followed by a final separation.

Less advantageously and less economiline and then wash the solution with furfuryl alcohol, no attempt being made to secure a homogeneous solution. Our process, therefore, in its broadest aspect, com-' prises the removal of color bodies from rosin y dissolving the rosin in asoline or an equivalent solvent as any llght petroleum distillate and removing color bodies there from by means of furfuryl alcohol.

It should also be understood that it is not substituted.

While we have specified gasoline as the solvent for the rosin and furfuryl alcohol, it is intended, by specifying that substance, to include operative equivalents, such as other petroleum distillates that have not too high a vaporizing temperature and which will be substantially immiscible with furfuryl alcohol. \Ve have even used the lighter lubricating distillates of mineral oil. A heavy hydrocarbon product, however, is undesirable, or even impracticable, because of its decomposing actioii on the rosin in the step of distilling ofi' the hydrocarbon.

The advantage of furfuryl alcohol is that it is capable of entering into solution with the gasoline at certain temperatures and of dissolving or absorbing the coloring bodies of the rosin, and yet can be largely thrown out of solution with the gasoline without giving up such coloring bodies.

The temperatures specified are largely a matter of choice, although it is desirable that the rosin-containing mixture shall be heated at the beginning to a temperature sufliciently high to form a substantially homogeneous solution, say in excess of 100 F. and that the refrigerating temperature at the end shall be below 25 F. Temperatures as high as 115 F. and as low as 10 F., as specified, are believed to be necessary to secure the best possible solution to start with and a maximum recovery of the highest grade rosin, although less nearly perfect results, with respect to quality and quantity, may be secured by departure from the above temperatures and it will be understood as indicated, that good results may be obtained by merely washing a solution of resin with furfuryl alcohol, followed by separation of the furfuryl alcohol and color bodies of the rosin dissolved therein from the rosin solution, no attempt being made to form a homogeneous solution as by the application of heat and the separation being effected with or without cooling.

The relative proportions of the constituents specified in the several successive compositions are illustrative merely, and are susceptible of considerable variation.

Having now fully described our invention, what we claim and desire to protect by Letters Patent is 2- I 1. In the method of refilling rosin, the step which includes subjecting rosin to treatment with furfuryl alcohol for the removal of color bodies from the rosin.

In-the method of refining rosin the step which includes subjecting rosin in solution to treatment with furfuryl alcohol for the removal of color bodies from the rosin.

3. The method of refining rosin, which includes dissolving rosin in a solvent normally substantiall immiscible with furfuryl alcoho treating the rosin solution with furfuryl alcohol for the extraction of color bodies from the rosin, separating furfuryl alcohol and color bodies from the rosin solu tion and recovering refined. rosin from the rosin solution.

4. The method of refining rosin, which includes dissolving rosin in a solvent normally substantially immiscible with furfuryl alcohol, treating the rosin solution with furfuryl alcohol for the-extraction of color bodies from the resin, reducing the temperature of the rosin solution, separating furfuryl alcohol and color bodies from the rosin solution and recovering refined rosin from f the rosin solution. 7

5. The method of refining includes dissolving rosin in gasoline, treating the gasoline-rosin solution with furfuryl alcohol for the extraction of color bodies from the rosin, separating furfuryl alcohol rosin, which i and color bodies from the gasoline-rosin solution and recovering refined rosin from the gasoline-rosin solution.

6. The method of refining rosin, which includes dissolving rosin in gasoline, treatin the gasoline-rosin solution with furfury alcohol for the extraction of color bodies from the rosin, reducing the temperature of the gasoline-rosin solution, separating tur furyl alcohol and color bodies from the asoline-rosin solution and recovering re ed rosin from the gasoline-rosin solution.

7. The method of refining rosin, which includes dissolving rosin in a solvent normally substantially immiscible with furfuryl alcohol, adding furfuryl alcohol to the rosin solution for the extraction of color bodies from the rosin, heating the rosin solution.

to a temperature at which furfuryl alcohol will go into solution therein, cooling the solution formed to a temperature at which furfuryl alcohol and extracted color bodies will be thrown out of solution from the rosin solution, separatin furfuryl alcohol and color bodies from the rosin solution and recovering refined rosin from the rosin solution.

8. The method of refining rosin, which in- .cludes dissolving rosin in gasoline, adding furfuryl alcohol to the asoline-rosin solution for the extraction 0% color bodies from the rosin, heating the gasoline-rosin solution to a temperature at which furfuryl alcohol will go intosolution 'in the gasoline-rosin solution, the solution formed to a temperaturezat which fiirfuryl alcohol and extracted color bodies will be thrown out of solution from the gasoline-rosin solution,

separating furfuryl alcohol and color bodies from the gasoline-rosin solution and recovering refined resin from the gasoline-rosin solution.

'9. The niethod of refining rosin, which includesdi'ssolving rosin in gasoline, adding furfuryl alcohol to the asoline-rosin solution for the extraction 0 f color bodies from 5 the rosin, heating the gasoline-rosin solution to a temperature at which furfuryl alcohol will go into solution in the gasoline-rosin solution, cooling the solution formed to a temperature of about 32 F., separating fur- 10 furyl alcohol and color bodies from the gasoline-rosin solution and recovering refined rosin from the gasoline-rosin solution,

In testimony of which invention, I, HARRY E. KAISER, have hereunto set my hand at Cologne, Germany, on this 2nd day of 15 August, 1926, a nd I, RoY S. HANCOCK, have hereunto set my hand at Kenvil, New Jersey, on this 17th day of July, 1926.

HARRY E. KAISER.- ROY S. HANCOCK. 

